Ce travail de thèse, débuté en 2015, a pour but de développer et d'étudier les propriétés de nouveaux liants polymères pour batteries Li-ion. Les synthèses organiques ainsi que leurs caractérisations associées et les tests électrochimiques ont été réalisées à Delft. Puis, des études de spectroscopie photo-électronique par rayons X (XPS) ont été réalisées à Pau pour déterminer et comprendre la réactivité de certain de ces nouveaux matériaux vis-à-vis du lithium. / This PhD work started in 2015, aimed to develop and investigate the properties of new polymers as binders for Li-ion batteries. Organic syntheses with associated characterizations and electrochemical tests were performed in Delft. Then, X-ray photoelectron spectroscopy studies were performed in Pau, to determine and understand the reactivity of some of these new materials toward lithium ions in coin cells.

The purpose of the study is to analyze the energy use of battery electric vehicles (BEVs), to compare their energy usage with other different vehicle technologies, and ultimately to determine their suitability for recreational use. The possibility of applying such vehicles into South Africa’s game reserves is researched in terms of energy costs and evaluated. Calculations were made based on actual existing routes found in the Kruger National Park, and are presently used by tourists for sightseeing and to access the different camps within the park. Calculations were made on the forces acting on a vehicle driving through the different routes and terrains. These forces were then translated into fuel or energy consumption and subsequently into fuel and energy prices. The entire exercise was performed on alternative vehicle technologies in a hypothetical scenario. The calculations investigated the energy consumption and efficiency of a battery electric vehicle (BEV) and other vehicle technologies such as fuel cell electric vehicle (FCEV), hybrid electric vehicle (HEV), and lastly the internal combustion engine (ICEV) vehicle. It was found that the energy consumption of each vehicle technology revealed similar trends and ranking on most routes. However on certain routes, the energy usage difference amongst the different vehicle technologies became more pronounced. This can be attributed to the continuous demand of energy by the vehicle to maintain forward motion. It was found that in general, irrespective of the route profile, the route surface or its total distance, the highest energy efficiency is achieved by the battery electric vehicle (BEV), followed by the fuel cell electric vehicle (FCEV) and then by the combined hybrid electric vehicle (HEV) and lastly by the internal combustion engine (ICEV) vehicle. / Electrical Engineering / M. Tech. (Electrical Engineering)

abstract: This thesis focused on physicochemical and electrochemical projects directed towards two electrolyte types: 1) class of ionic liquids serving as electrolytes in the catholyte for alkali-metal ion conduction in batteries and 2) gel membrane for proton conduction in fuel cells; where overall aims were encouraged by the U.S. Department of Energy. Large-scale, sodium-ion batteries are seen as global solutions to providing undisrupted electricity from sustainable, but power-fluctuating, energy production in the near future. Foreseen ideal advantages are lower cost without sacrifice of desired high-energy densities relative to present lithium-ion and lead-acid battery systems. Na/NiCl2 (ZEBRA) and Na/S battery chemistries, suffer from high operation temperature (>300ºC) and safety concerns following major fires consequent of fuel mixing after cell-separator rupturing. Initial interest was utilizing low-melting organic ionic liquid, [EMI+][AlCl4-], with well-known molten salt, NaAlCl4, to create a low-to-moderate operating temperature version of ZEBRA batteries; which have been subject of prior sodium battery research spanning decades. Isothermal conductivities of these electrolytes revealed a fundamental kinetic problem arisen from "alkali cation-trapping effect" yet relived by heat-ramping >140ºC. Battery testing based on [EMI+][FeCl4-] with NaAlCl4 functioned exceptional (range 150-180ºC) at an impressive energy efficiency >96%. Newly prepared inorganic ionic liquid, [PBr4+][Al2Br7-]:NaAl2Br7, melted at 94ºC. NaAl2Br7 exhibited super-ionic conductivity 10-1.75 Scm-1 at 62ºC ensued by solid-state rotator phase transition. Also improved thermal stability when tested to 265ºC and less expensive chemical synthesis. [PBr4+][Al2Br7-] demonstrated remarkable, ionic decoupling in the liquid-state due to incomplete bromide-ion transfer depicted in NMR measurements. Fuel cells are electrochemical devices generating electrical energy reacting hydrogen/oxygen gases producing water vapor. Principle advantage is high-energy efficiency of up to 70% in contrast to an internal combustion engine <40%. Nafion-based fuel cells are prone to carbon monoxide catalytic poisoning and polymer membrane degradation unless heavily hydrated under cell-pressurization. This novel "SiPOH" solid-electrolytic gel (originally liquid-state) operated in the fuel cell at 121oC yielding current and power densities high as 731mAcm-2 and 345mWcm-2, respectively. Enhanced proton conduction significantly increased H2 fuel efficiency to 89.7% utilizing only 3.1mlmin-1 under dry, unpressurized testing conditions. All these energy devices aforementioned evidently have future promise; therefore in early developmental stages. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2014

Doctor of Philosophy / Department of Chemistry / Jun Li / Electrical energy storage (EES) is crucial in todays’ society owing to the advances in electric cars, microelectronics, portable electronics and grid storage backup for renewable energy utilization. Lithium ion batteries (LIBs) have dominated the EES market owing to their wide use in portable electronics. Despite the success, low specific capacity and low power rates still need to be addressed to meet the increasing demands. Particularly, the low specific capacity of cathode materials is currently limiting the energy storage capability of LIBs. Vanadium pentoxide (V₂O₅) has been an emerging cathode material owing to its low cost, high electrode potential in lithium-extracted state (up to 4.0 V), and high specific capacities of 294 mAh g⁻¹ (for a 2 Li⁺/V₂O₅ insertion process) and 441 mAh g⁻¹ (for a 3 Li⁺/V₂O₅ insertion process). However, the low electrical conductivities and slow Li⁺ ion diffusion still limit the power rate of V₂O₅. To enhance the power-rate capability we construct two core-shell structures that can achieve stable 2 and 3 Li⁺ insertion at high rates. In the first approach, uniform coaxial V₂O₅ shells are coated onto electrospun carbon nanofiber (CNF) cores via pulsed electrodeposition. The materials analyses confirm that the V₂O₅ shell after 4 hours of thermal annealing at 300 °C is a partially hydrated amorphous structure. SEM and TEM images indicate that the uniform 30 to 50 nm thick V₂O₅ shell forms an intimate interface with the CNF core. Lithium insertion capacities up to 291 and 429 mAh g⁻¹ are achieved in the voltage ranges of 4.0 – 2.0 V and 4.0 – 1.5 V, respectively, which are in good agreement with the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion. Moreover, after 100 cycles, remarkable retention rates of 97% and 70% are obtained for 2 and 3 Li⁺/V₂O₅ insertion, respectively. In the second approach, we implement a three-dimensional (3D) core-shell structure consisting of coaxial V₂O₅ shells sputter-coated on vertically aligned carbon nanofiber (VACNF) cores. The hydrated amorphous microporous structure in the “as-deposited” V₂O₅ shells and the particulated nano-crystalline V₂O₅ structure formed by thermal annealing are compared. The former provides remarkably high capacity of 360 and 547 mAh g⁻¹ in the voltage range of 4.0 – 2.0 V and 4.0 – 1.5 V, respectively, far exceeding the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion, respectively. After 100 cycles of 3 Li⁺/V₂O₅ insertion/extraction at 0.20 A g⁻¹ (~ C/3), ~ 84% of the initial capacity is retained. After thermal annealing, the core-shell structure presents a capacity of 294 and 390 mAh g⁻¹, matching well with the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion. The annealed sample shows further improved stability, with remarkable capacity retention of ~100% and ~88% for 2 and 3 Li⁺/V₂O₅ insertion/extraction. However, due to the high cost of Li. alternative approaches are currently being pursued for large scale production. Sodium ion batteries (SIB) have been at the forefront of this endeavor. Here we investigate the sodium insertion in the hydrate amorphous V₂O₅ using the VACNF core-shell structure. Electrochemical characterization was carried out in the potential ranges of 3.5 – 1.0, 4.0 – 1.5, and 4.0 – 1.0 (vs Na/Na⁺). An insertion capacity of 196 mAh g-1 is achieved in the potential range of 3.5 – 1.0 V (vs Na/Na⁺) at a rate of 250 mA g⁻¹. When the potential window is shifted upwards to 4.0 – 1.5 V (vs Na/Na⁺) an insertion capacity of 145 mAh g⁻¹ is achieved. Moreover, a coulombic efficiency of ~98% is attained at a rate of 1500 mA g⁻¹. To enhance the energy density of the VACNF-V₂O₅ core-shell structures, the potential window is expanded to 4.0 – 1.0 V (vs Na/Na⁺) which achieved an initial insertion capacity of 277 mAh g⁻¹. The results demonstrate that amorphous V₂O₅ could serve as a cathode material in future SIBs.

La question du stockage de l’énergie est actuellement au cœur de nombreuses problématiques internationales. Le développement de systèmes de stockage tels que les batteries lithium ion (LIB) et sodium ion (SIB) fait donc l’objet aujourd’hui de nombreuses recherches. Dans ce contexte, les matériaux lamellaires présentant un espace inter-feuillet permettant une insertion d’espèces cationiques semblent idéals dans le cadre d’une utilisation comme matériau d’électrode positive pour ces systèmes LIB et SIB. Parmi ces structures le pentoxyde de vanadium, sous sa forme alpha est un composé modèle présentant de nombreux intérêts pour les batteries au lithium. Ce matériau présente en outre de nombreux polymorphes stables autorisant un large champ d’étude de ce composé.Dans cette thèse, nous nous sommes intéressés au polymorphe gamma’-V2O5 présentant une structure lamellaire à très large inter-feuillet laissant présager une insertion d’espèces cationiques facilitée et donc des performances électrochimiques accrues. Le but de cette thèse a consisté à étudier les propriétés électrochimiques et la réponse structurale de ce composé vis-à-vis de l’insertion des ions lithium et sodium.La première partie de cette thèse propose une analyse bibliographique de l’état de l’art sur les accumulateurs lithium-ion et sodium.Dans une seconde partie les données concernant l’insertion du lithium et du sodium dans le composé alpha-V2O5 sont présentées. Les propriétés électrochimiques et structurales de ce matériau d’insertion permettront de mettre en avant l’intérêt de l’utilisation du polymorphe gamma’-V2O5 comme matériau d’électrode positive pour les systèmes LIB et SIB.Une troisième partie de ce mémoire présente la synthèse et la caractérisation du polymorphe gamma’-V2O5. L’étude complète de ce système est présentée dans le cas de l’insertion du lithium avec une étude des performances électrochimiques, une étude cinétique de la réaction d’insertion réalisée par spectroscopie d’impédance complexe et la description des changements structuraux étudiés pas diffraction des rayons X et par spectroscopie Raman.Dans une quatrième partie, l’insertion électrochimique du sodium dans le polymorphe gamma’-V2O5 est étudiée en suivant la même démarche. Le mécanisme structural impliqué dans le fonctionnement électrochimique est résolu. La formation d’un bronze de vanadium au sodium jamais encore décrit, gamma-Na0,97V2O5, est révélée et la détermination de sa structure est réalisée. Les caractéristiques électrochimiques remarquables de gamma’-V2O5, et notamment sa tension élevée de 3,3V et son excellente stabilité en cyclages, permettent de situer ce composé parmi les cathodes les plus performantes pour batterie au sodium / The question of energy storage is currently at the heart of many international issues. The development of storage systems such as lithium ion (LIB) and sodium ion (SIB) batteries is therefore today the subject of many researches.In this context, layered materials having an interlayer space allowing insertion of cationic species seem ideal in the context of use as a positive electrode material for these LIB and SIB systems. Among these structures, vanadium pentoxide, in its alpha form, is a model compound with many advantages as an attractive cathode material for lithium batteries. This material also has numerous stable polymorphs allowing a wide field of study of this compound.In this thesis we were interested in the gamma'-V2O5 polymorph, which exhibits a layered structure with very large interlayer space allowing an easier insertion. Therefore, increased electrochemical performances are expected for this compound. The aim of this thesis was to study the electrochemical properties and the structural response of this compound toward the insertion of lithium and sodium ions.The first part of this thesis proposes a review of the current literature studies devoted to lithium-ion and sodium batteries.In a second part, a thorough study of the electrochemical lithium and sodium insertion in the alpha-V2O5 phase are depicted. The electrochemical and structural properties of alpha-V2O5 will make it possible to highlight the advantage of using the polymorph gamma'-V2O5 as a positive electrode material for LIB and SIB.The third part of this thesis presents the synthesis and characterization of the gamma'-V2O5 polymorph. The complete study of this system is presented in the case of the insertion of lithium with a study of electrochemical performances, a kinetic study of the insertion reaction carried out by complex impedance spectroscopy and a description of the structural changes studied by X-ray diffraction and by Raman spectroscopy.In the fourth chapter, the insertion of sodium into the polymorph gamma'-V2O5 is studied, using the same approach than that adopted in the case of lithium. The structural mechanism involved during the electrochemical process is solved. The formation of a new sodium vanadium bronze, gamma-Na0.97V2O5 , is revealed and its structural determination is carried out. Due to its remarkable electrochemical characteristics, especially its high voltage of 3,3V and excellent cycling stability, the gamma'-V2O5 oxide ranks among the most performant cathode materials for sodium batteries

Orientador: Celia Marina de Alvarenga Freire / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-28T23:57:37Z (GMT). No. of bitstreams: 1 Silva_JoseRochaAndradeda_M.pdf: 3642803 bytes, checksum: e91a23ef6d38a032df085e07b32843f1 (MD5) Previous issue date: 2000 / Resumo: Os acumuladores de energia estacionários devem ser periodicamente avaliados quanto à sua capacidade de carga, visando assegurar que sua energia acumulada poderá ser prontamente utilizada, quando das falhas do sistema de alimentação convencional. Normalmente, essas avaliações são realizadas através dos testes de capacidade, que apresentam como principais desvantagens, o fato do banco de baterias permanecer indisponível, durante a realização do teste, e o desperdício da energia acumulada nas baterias. Neste trabalho á avaliada a potencialidade do método de espectroscopia de impedância eletroquímica como ferramenta na determinação do estado-de-carga de baterias chumbo-ácidas, através da análise das relações dos seus parâmetros eletroquímicos e sua quantidade de carga armazenada / Abstract: Stationary lead-acid batteries must have their charge capacity periodically evaluated in order to assure that they are ready to supply energy during conventional supplier faults. Normally, these evaluations are conduct by capacity tests, which present these main disadvantages: batteries remain unavailable while tests are conducted and total energy accumulated in batteries is dissipate during the tests. In this work electrochemical impedance spectroscopy is evaluated as a tool to assess the lead., acid batteries¿ state-of-charge, by analysing the co-relations between battery electrochemical parameters and its stored energy / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

One of the technical advances made by the lead-acid battery industry in the field of portable power supply was the development of the valve regulated lead-acid battery (VRLA). This battery reduced the necessity for periodic servicing in terms of having to replenish the cells with distilled water. Further, this new type of battery can now be installed near sensitive electronic equipment without the danger of acid spill or dangerous fumes being emitted. In addition, longer service performance is achieved in terms of life cycle capacity, when compared to the conventional flooded type batteries. However, the new type of battery requires the manufacturing of high precision electrodes and components with low tolerances for error. In order for the manufacturers to produce such a premium product, a thorough understanding of the electrochemistry of the inner components is necessary. None of the South African lead-acid battery manufacturers are currently making VRLA batteries to supply a very competitive global market, where a large range of sizes and capabilities are available. In order to introduce the VRLA battery into such a competing market in South Africa, a niche area for its application was identified in order to establish the viability of manufacturing such a battery locally. This is done by integrating the VRLA concept into an existing battery, such as the miners cap lamp (MCL) battery. Its application is specific with well-defined performance criteria in a relatively large consumable market in the South African mining industry. The study looked at various components within a local manufacturing environment that required a better understanding and modification of the processes to build VRLA MCL batteries. This included a detailed study of the manufacturing processes of the positive electrode. The study involved the investigation of the types of grid alloys used, the type of electrode design, such as tubular or flat plate, the addition of redlead to the paste mixing process and subjecting the batteries to accelerated life cycle testing. A better understanding of the oxygen recombination cycle was also performed in order to evaluate the correct use of certain design criteria in the manufacturing process. This included the study of the pressure release valve and the type of positive electrode used. The study also looked at developing an inexpensive analytical technique to evaluate the porosity of cured and formed electrodes using a glycerol displacement method. The monitoring of the state of health (SoH) of VRLA batteries on a continuous basis is an important parameter in unique applications such as remote power supply. A device was developed to monitor the SoH of VRLA batteries on a continuous basis. The working principle of the device was tested on a MCL VRLA battery. With the development of other types of VRLA batteries for specific applications such as in stand-by power supplies, the monitoring device would then be integrated in the battery design.

Le domaine du transport aérien est en plein effort de réduction de ses émissions de gaz à effet de serre. Les PEMFC sont sérieusement envisagées afin d'introduire d'avantage d'énergie électrique à bord des avions. On se propose d'étudier la faisabilité de la propulsion d'avions légers alimentés par des systèmes pile à combustible hybridés. On étudie plus spécifiquement un système hybride PEMFC / Batteries Li-Ion produisant un total de 40 kW (20 kW PàC + 20 kW Li-Ion) permettant de propulser un avion léger biplace. Le premier aspect de cette étude est la navigabilité des PEMFC, c'est à dire leur aptitude à fonctionner en milieu aérien. Le second aspect est l'architecture électrique du système hybride, son dimensionnement et son comportement lors de différents profils de vol. Des essais expérimentaux en altitude sont menés et permettent de quantifier la diminution des performances de PàC aérobies liée à la diminution de pression ambiante. Grâce à ces essais et à un modèle numérique de PàC, on compare les technologies aérobies et anaérobies pour différents profils de vol. Un bilan des masses et des volumes associé à chacune de ces deux technologies est dressé. Par ailleurs, des essais en inclinaisons de systèmes PEMFC sont réalisés. L'hybridation directe de PEMFC avec des batteries Lithium est étudiée numériquement et expérimentalement. Un modèle Matlab Simulink de PàC et de batteries Lithium est développé afin de prédire le comportement du système hybride direct et de le dimensionner. Enfin, un banc expérimental d'hybridation directe est réalisé et des essais sont menés, révélant l'intérêt de cette architecture innovante. / The domain of air transport is working at reducing its emissions of greenhouse gases. PEMFC are seriously considered as electrical source for future aircraft. The present study focusses on the feasibility of propulsion of a light aircraft powered by hybridized PEMFC systems. The hybrid PEMFC / Li-Ion batteries system studied here produces 40 kW (20 kW PEMFC + 20 kW Li-Ion) and should be able to power a two-seat light aircraft. The first part of the study is dedicated to PEMFC airworthiness, meaning their capacity to work properly in aeronautical conditions. The second part is dedicated to the hybrid system electrical architecture, its dimensioning and its response to various flight profiles. Aerobic PEMFC performance loss due to drop in ambient pressure is quantified thanks to experiments at various altitude. Thanks to these measurements and to a numerical model, aerobic and anaerobic PEMFC are compared according to various flight profiles. A mass and volume balance of each technology is drawn up. In addition, inclination tests of PEMFC systems are performed. Direct hybridization of PEMFC and Li-Ion batteries is studied numerically and experimentally. A Matlab Simulink model of PEMFC and battery is developed in order to forecast the hybrid system's response and to size it. Finally, an experimental bench is settled up and tests are led, proving the interest of such an innovative architecture.

La voie hydrométallugique représente une alternative pour la récupération des métaux de valeur tels que le nickel et le cobalt contenus dans les batteries Li-ion usagées. La première étape du procédé hydrométallurgique, l'étape de lixiviation a été optimisée grâce à l'étude du comportement du matériau actif d'électrode positive LiNi1/3Mn1/3Co1/3O2 (NMC) qui s'avère être le candidat idéal pour les batteries de véhicules électriques. Tout d'abord, l'étude des aspects thermodynamiques de la réaction de dissolution a permis de prédire le comportement du NMC dans divers acides. Puis, l'approche cinétique a conduit à l'élucidation du mécanisme se produisant lors de l'étape de lixiviation et à la mise en évidence de l'étape cinétiquement déterminante de la dissolution. Ce mécanisme a par la suite été généralisé aux autres matériaux couramment rencontrés dans les batteries Li-ion. L'impact d'agents réducteurs minéraux, organiques et métalliques pour promouvoir la dissolution du NMC a été évalué. Cette approche compare l'effet de réactifs à faible (acides sulfurique et chlorhydrique) et fort (acides citrique, oxalique et formique et peroxyde d'hydrogène) pouvoir réducteur ainsi que celui du cuivre et de l'aluminium provenant des collecteurs de courants des batteries Li-ion. Cette étude soulève le fort intérêt de l'emploi des collecteurs de courant présents de manière inhérente dans la fraction traitée par hydrométallurgie. / Basic hydrometallurgical routes represent an alternative to recover valuable metals such as nickel and cobalt from spent Li-ion batteries. The first step of hydrometallurgical process, lixiviation step is optimized by studying the behaviour of LiNi1/3Mn1/3Co1/3O2 (NMC) positive electrode active material, due to its good performances which make it an adequate candidate for the electric vehicles. First of all, the study of thermodynamic aspects allows predicting the behaviour of NMC material in various acidic media. Then, the kinetic approach leads to define the mechanism occurring during the leaching step and to outline the rate-limiting step of the dissolution. The reductive effect of mineral, organic and metallic reducing agents to promote leaching of NMC material is evaluated. The approach comparatively evaluates the reducing power impact of weak (sulfuric and hydrochloric acids), strong reducing agents (citric, oxalic and formic acids and hydrogen peroxide) and copper and aluminum from Li-ion batteries current collectors. This work points out the strong interest to advantageously use current collectors inherently present in the fraction treated by hydrometallurgy.

Les batteries lithium-ion sont largement utilisées comme source d'énergie pour les appareils électroniques portables. L'oxyde de fer (principalement α-Fe2O3), l'un des oxydes de métal de transition les plus important, a suscité l’intérêt scientifique depuis qu'il a été reporté comme matériau d'anode pour les batteries lithium-ion en raison de sa capacité théorique élevée (1007 mAh g-1), de son respect de l'environnement, de son abondance et de son faible coût. Dans cette thèse, une électrode modèle en couche mince d'oxyde de fer a été préparée par simple oxydation thermique à 300 °C dans l'air d'un substrat de fer métallique pur, utilisé aussi comme collecteur de courant. Une variété de techniques d'analyse, électrochimiques (CV, EIS et cyclage galvanostatique), spectroscopiques (XPS, ToF-SIMS) et microscopiques (MEB et AFM), ont été mises en oeuvre pour étudier les mécanismes réactionnels et la chimie de surface de l'oxyde de fer à différents stades de lithiation/délithiation et cyclage. / Lithium-ion batteries (LIBs) are widely used as power sources for portable electronic devices. Iron oxide (mainly α-Fe2O3), as one of the most important transition metal oxide, has attracted attention due to its high theoretical capacity (1007 mAh g-1), environmental friendliness, abundance and low cost since reported as anode material for LIBs. In this thesis, an iron oxide thin film model electrode was prepared by simple thermal oxidation of pure metallic iron substrate at 300 oC in air, also used as a current collector. Electrochemical methods (CV, EIS and galvanostatic cycling) were combined with surface (XPS, ToF-SIMS) and microscopic (SEM, AFM) analytical techniques to investigate the reaction mechanisms and the surface chemistry of the iron oxide thin film at different stages of lithiation/delithiation and upon cycling.